Roads and landslides in Nepal: how development affects environmental risk

Abstract

Abstract. The number of deaths from landslides in Nepal has been increasing dramatically due to a complex combination of earthquakes, climate change, and an explosion of informal road construction that destabilizes slopes during the rainy season. This trend will likely rise as development continues, especially as China's Belt and Road Initiative seeks to construct three major trunk roads through the Nepali Himalaya that adjacent communities will seek to tie in to with poorly constructed roads. To determine the effect of these informal roads on generating landslides, we compare the distance between roads and landslides triggered by the 2015 Gorkha earthquake with those triggered by monsoon rainfalls, as well as a set of randomly located landslides to determine if the spatial correlation is strong enough to further imply causation. If roads are indeed causing landslides, we should see a clustering of rainfall-triggered landslides closer to the roads that accumulate and focus the water that facilitates failure. We find that in addition to a concentration of landslides in landscapes with more developed, agriculturally viable soils, that the rainfall-triggered landslides are more than twice as likely to occur within 100 m of a road than the landslides generated by the earthquake. The oversteepened slopes, poor water drainage and debris management provide the necessary conditions for failure during heavy monsoonal rains. Based on these findings, geoscientists, planners and policymakers must consider how road development affects the physical (and ecological), socio-political and economic factors that increase risk in exposed communities, alongside ecologically and financially sustainable solutions such as green roads.

Invited perspectives: Mountain roads in Nepal at a new crossroads

“…However, benefits of roads need to be weighed alongside evidence that roads may benefit nonpoor households more, perhaps making development less even (Hettige, 2006). Furthermore, other impacts, such as increased environmental hazards, pollution, crime and unwanted cultural influences, are often overlooked (Blaikie et al, 1976;Hettige, 2006;Jaboyedoff et al, 2016;Murton, 2016). This paper builds on research and publications questioning the aspirations of the government of Nepal as early as the 1970s and 1980s.…”

“…Studies have demonstrated that roads are one of the 658 K. Sudmeier-Rieux et al: Invited perspectives: Mountain roads in Nepal at a new crossroads greatest anthropogenic drivers of environmental degradation, erosion and landslides in Nepal (Petley et al, 2007;Froude and Petley, 2018;Vuilliez et al, 2018). This situation is worsening due to the intensifying rainfall during the monsoon, largely attributed to climate change (Petley et al, 2007;Bharti et al, 2016;Devkota et al, 2018;Froude and Petley, 2018), which has led to a greater occurrence of landslides, especially in the middle hills (McAdoo et al, 2018). The possibility of an earthquake of even greater magnitude than the 2015 Gorkha earthquake (M 7.8) raises concerns about poorly designed roads increasing the likelihood of catastrophic landslides (Singh, 2018).…”

Framework for Assessment of Eco-Safe Rural Roads in Panchase Geographic Region in Central–Western Nepal Hills

“…Investment in roads is considered to bring multiple opportunities for enhancing livelihoods [2]. However, studies showed that, over the period of about 20 years, haphazard construction of rural roads increased exponentially in Nepal [3,4], and these roads are mostly unplanned and non-engineered [5], resulting in many slope failures that can create catastrophic disasters such as landslides. Unplanned human interventions, such as rural road construction, quarrying or poor terrace management can increase the fragility of slopes and, consequently, the occurrence of landslides and erosion [6].…”

“…Unplanned human interventions, such as rural road construction, quarrying or poor terrace management can increase the fragility of slopes and, consequently, the occurrence of landslides and erosion [6]. Landslides not only destroy lives and livelihood activities, but they also block roads while causing long-term environmental degradation [3,7]. Nepal's hill roads are impacted by landslides mostly triggered by intense rainfall [8].…”

Community-based landslide hazard probability and risk assessment: A case in west Hubei, China

“…Guidelines for landslide risk zoning and land use planning with the framework, definitions and recommendations were provided for different clearly defined scales (Fell et al, 2008a). Also, research work highlighting landslide risks at a community-level has recently been tested, and some of the result reached are open for the public (Abdulwahid and Pradhan, 2016;Chen et al, 2016a;Erener and Düzgün, 2012;Liu et al, 2016;McAdoo et al, 2018;Paliaga et al, 2019). Paliaga et al (2019), for example, have used a spatial multi-criteria analysis technique (SMCA) to mitigate geo-hydrological risk in a small but densely-populated catchment, with descriptive parameters of the extent of urban development and elements at risk.…”